[Dune] Trouble with matrix distribution

[Kumar, Paras]

Hi,

I'am working on a problem which involves solving a linear equation 
system(arising out of an FE discretization) in parallel.

The matrix A is created in serial on the master process and is then to 
be redistributed on the slave processes. For this task I adopt the 
technique as described by here:

https://www.dr-blatt.de/blog/posts/creating_a_parallel_istl_matrix/


The code compiles and run without any segmentation faults but the 
redistribution doesn't seem to happen. I get the following message when 
I run the code on 4 MPI processes.

PARMETIS ERROR: Poor initial vertex distribution. Processor 3 has no 
vertices assigned to it!
PARMETIS ERROR: Poor initial vertex distribution. Processor 1 has no 
vertices assigned to it!
PARMETIS ERROR: Poor initial vertex distribution. Processor 2 has no 
vertices assigned to it!

Could someone please help me finding where I go wrong.

With best regards
Paras Kumar